The invention relates to a closure device connecting two parts.
Such a closure device has a first connecting module and a second connecting module, which can be arranged on each other in a closing direction and are mechanically latched to each other in a closing position. In addition, magnetic means are provided, which establish a magnetic attraction force between the connecting modules for assisting the transfer of the connecting modules into the locking position. Due to a movement of the first connecting module or a part of the first connecting module in an opening direction, which differs from the closing direction, the first connecting module can be released from the second connecting module in order to open the closure device in this manner.
In case of a closure device of this kind known from WO 2008/006357 A2 two connecting modules are applied to each other in a vertical closing direction and mechanically latched in doing so. Due to the fact that a magnet is arranged on the first connecting module as well as on the second connecting module, respectively, or a magnet is arranged on one side and a magnetic anchor on the other side the establishing of the mechanical latching and thus the transfer of the closure device into the closing position is magnetically supported. If the magnet is suitably dimensioned, the closure of the closure device occurs almost automatically, when the connecting modules are approaching each other. When moving or rotating the first connecting module relative to the second connecting module, then the mechanical latching can also again be released, wherein simultaneously the magnetic means are sheared off from each other by a lateral movement and thus are removed from each other.
Closure devices of this kind provide on one side in their closing position a safe and resilient connection of two parts to each other and can on the other side be closed in a simple manner and can be again opened in a haptically comfortable manner. The fields of application of such closure devices extend to devices of general kind for (releasable) connecting two parts, as for instance closures of bags, lits or covers, connecting devices for belts or ropes or other components and such.
It is desirable to design the magnetic means, for instance realised by magnets or a magnet and a magnetic anchor, in a small dimension in order to save costs for magnets and also to keep the construction volume of the closure device at a minimum. However, when dimensioning the magnetic means it has also to be considered that these have to effect a sufficient magnetic force in order to establish an attraction force between the connecting modules, which allows for an automatic mechanical latching as far as possible.
In order to be able to close for instance a closure device according to WO 2008/006357 A2 the connecting modules are applied to each other. If the application occurs exactly in the closing direction in case of magnetic means being aligned exactly to each other, a large magnetic attraction force acts between the connecting modules so that the transfer in the closing position is assisted in a desirable manner by the effect of the magnetic means. If the magnetic means are not exactly aligned towards each other, an alignment of the connecting modules towards each other occurs by the magnetic attraction force, that means the magnetic attraction force pulls the connecting modules with alignment of the magnetic means towards each other and into the closing position, in which the magnetic means shall be aligned congruent and frontal to each other as far as possible.
This alignment of the connecting modules to each other when closing the closure device is desirable. A complete optimal alignment occurs practically only, if the magnetic attraction force of the magnetic means comprises a pre-determined strength and the magnetic means are accordingly large dimensioned. If the magnetic means are small dimensioned, it can occur in case of a non-exact alignment of the connecting modules to each other during closing the closure device that the magnetic attraction force is not sufficient in order to align the connecting modules to each other and to transfer said modules automatically into the closing position. The reason is that in case of an inexact positioning of the connecting modules to each other, the respective magnetic means (for instance magnet and anchor) do not exactly face each other, but are rather laterally shifted to each other so that the acting magnetic contraction force is smaller compared to an exact alignment of the magnetic means to each other. If this reduced magnetic attraction force is not sufficient in order to establish the mechanical latching, the connecting modules remain in a in-between position, in which the closure device is not completely closed; an automatic transfer into the closing position does not occur.
In order to achieve an automatic latching also in case of inexact application of the connecting modules to each other for closing the closure device until now an overdimensioning of the magnetic means was required, what made the closure device expensive and required a comparable large construction space.